Synopsys激活设备与多级模拟：概述说明书

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Active Device Utilities and Multi-Level Simulation
An Overview
Outline
•Introduction
•Multi-Physics Utility –Carrier Effects •Solar Cell Utility –Lasermod Option •Tapered Laser Utility
•Multi-Level Simulation
Some active applications may require multiple tools. These tools may be used together manually, or automated via a utility:
•Utility Interaction involves 1 or 2 directional data flow:
–Multi-Physics Utility (Carrier effects)
–Solar Cell Utility (Lasermod option)
–Tapered Laser Utility
•Multi-Level Interaction involves 1 directional data flow:
–OptSIM-LaserMOD(Parameter Extraction)
–ModeSYS-LaserMOD(Near/Far-Fields)
A utility is an automated process for addressing a particular application (solar cell, modulator, etc…).
•It is not a simulator, but uses one or more simulators to generate specific data.
•It also provides some post-processing of the data to generate application specific performance results.
Active Device Simulator Takes the mode(s) or field from a passive tool & produces a complex index that includes the various perturbations from carriers & material gain/loss.Passive Device Simulator Takes the complex index, merges it with the unperturbed structure, and solves for the mode(s) or
field.
(each 2D ‘slice’) Operational Scheme of a 2D Utility:
Operational Scheme of a 3D Utility:
• A collection of 2D‘slices’ are simulated iteratively until convergence is reached.
There are 2 types of Multi-Level Simulation, extraction and data file exchange:•Laser modeling may be achieved jointly with the device and system tools via the BestFIT Laser T oolkit, which can extract system level model parameters from active device level simulation results.•Field and mode profiles generated by device tools may be
passed to ModeSYS to study spatial effects at system level.
(BestFit Toolkit)Modes & Transfer Functions
Outline
•Introduction
•Multi-Physics Utility –Carrier Effects •Solar Cell Utility
•Tapered Laser Utility
•Multi-Level Simulation
•The Multi-Physics Utility includes the following physical effects:–Electro-optic
–Thermo-optic
–Stress-optic
–Carrier effects
•Carrier effects require the use of LaserMOD.
•They are necessary for simulation Electro-absorptive and Electro-refractive Modulators.
•Of current interest are those implemented in silicon-on-insulator (SOI).
•Multi-Physics Utility (carrier effects)
–Extends 2D active device simulation of free carrier effects to 3D for the case of waveguide circuits.–Uses BeamPROP+ LaserMOD.
•Addresses design improvements such as:
–Modulation speed and ON/OFF contrast,
–Compactness of geometry.
•Arbitrary waveguide circuit layouts can be accommodated.•All simulations handled transparently by the RSoft CAD.
•In some cases, modulator performance can be determined by an analytic expression: (1-cos(K0*(Neff-Neff0)*L))/2
•In others, a 3D optical solution is required.
•The 3D structure can be constructed from a set of 2D complex index cross-sections obtained from active simulation, at a given applied bias.•3D propagation can then be performed with BPM.
•Setting up the carrier effect is nearly identical to setting up an electro-optic problem.
•The desired structure is drawn and electrodes are place appropriately. The voltage is then set in the control parameter of the bias electrode(s).•Project materials are set as
in the Material Editor, as
before, but when carrier-
effects are used, an active
semiconductors structure, with
doping and alloy composition,
must be defined. This is done
on the Semiconductor T ab.
•The following example is a ridge waveguide implemented in SOI.
•A voltage bias is applied to the electrode on top of the ridge. This voltage may be controlled from the utility dialog.
•The Multi-Physics Utility will simulate the steady-state behavior at the specified voltage.
•But the time/frequency response is also available, and is enabled from the Carrier Options Dialog, within the utility.
•When the Multi-Physics Utility is run directly from the dialog, the real & imaginary index perturbations that result from the applied voltage, are generated.
•Additionally, the intermediate solutions (electron & hole densities, and electrostatic potential) are also produce.
•Furthermore, I-V, C-V, and R-V plots are generated,
•If enabled, the frequency response will be output as well.
•All results will be displayed by the DataBROWSER, which is invoked automatically at the end of the simulation.
•Standard propagation and mode solving will also reflect the presence of carrier effects, provided these effects have been enabled in the Utility Dialog.
•For example, the mode calculations shown below, are at different voltages, and therefore have different Neff’s.
V=0 (volt)V=1 (volt)
•A simple validation example is now presented: an SOI-based Mach-Zehnder Modulator.
•Reference:”Modeling and Characterization of Mach-Zehnder Silicon Electro-optical Modulators,” G.-R. Zhou et.al., CLEO/QELS 2008.
•The simulation is conducted as follows:
–The Neff of the waveguide vs applied voltage is determined from
a rigorous simulation using the Multi-Physics Utility.
–The final modulator transmission characteristics are then
tabulated from an analytic function of the waveguide Neff.
–A full BPM approach could also have been used to determine the modulator transmission, but with a simulation time cost.
•The device is an MZ modulator with .25mm long branches.
•The waveguide is silicon with a 500nm x 200nm cross-section, set between lateral n-& p-contacts.
•The voltage on one contact varies between 0 and 1.2 Volts, but remains 0 Volts on the other.
V=0 volts V=0-1.2 volts
contacts
•Simulation results for the I-V curves and modulator transmission characteristics are shown below.
Measured
and
S-Device
simulation
Multi-Physics
•Simulation results for the frequency response (|S 21|2) are shown below. All show the 3dB point to be around 0.4GHz .Measured and S-Device simulation
Multi-Physics Utility simulation Multi-Physics Utility
Outline
•Introduction
•Multi-Physics Utility
•Solar Cell Utility –Lasermod Option •Tapered Laser Utility
•Multi-Level Simulation
•This utility computes the cell efficiency of a solar cell device.
•It will also compute the collection efficiency if LaserMOD used, otherwise this must be input by the user.
•The optical confienement is computed via DiffractMOD or FullWAVE.•The incident spectrum may be selected as the Solar Spectrum at sea level or input via User Defined file.
•Electrical characteristics are determined via the ideal diode equation or by LaserMOD simulation.
•Simulation results are automatically combined to produce cell efficiency and other outputs of interest.
•For example, optical confinement and thus cell efficiency may be enhanced by randomly textured interfaces.
•Simulation of this requires FDTD.
•Absorption is tabulated in a particular region via the “Absorption Monitor” (FullWAVE) or in the entire structure.
•This is done for a sampled set of wavelengths within the incident spectrum (two wavelengths are shown below.
•From this absorption, Jsc (short circuit
current) is calculated. From Jsc and
several input parameters such as
collection efficiency and Voc (open
circuit voltage) the Ideal diode equation may be used to generate an I-V curve.
…or…
•Using absorption at each wavelength, the photo-generated carrier distribution is obtained and the electronic transport, is solved leading directly to a non-
is output.
•From the I-V curve, the optimum bias point can be found, giving filling-factor
and cell efficiency.
Outline
•Introduction
•Multi-Physics Utility •Solar Cell Utility •Tapered Laser Utility •Multi-Level Simulation
Most active device characteristics can be extracted from 2D simulations, but some cases require 3D, for example:•When the lasers geometry varies along the device.
–Tapered Ridge
–Tapered electrode
•When 3D spatial effects are of interest (even in straight ridge).
–Filamentation
–Transverse + Longitudinal spatial hole burning
•The Tapered Laser Utility extends the 2D active device simulation to 3D.
•It can analyze the optical and electronic properties of waveguide lasers with straight and tapered (or slowly varying) sections.
•It provides a Self-consistent simulation using BeamPROP for the Optical propagation, and LaserMOD for the electronic transport.•Outputs include the field at every slice, L-I-V curves, and the far field from each facet.
•The active simulation produces complex index.•The passive simulation propagates the field.•The utility ensures self-consistency for all the slices.
•The full structure is comprised of all the slices, which are coupled to each other via the propagating field.
•The electrical simulations of each slice are independent from each other.
•In the gain guiding example distributed with the software, the tapered region is defined purely by the top (tapered) electrode.
•The straight section is defined by a ridge (and electrode)
•Since the tapered region is defined purely by the top electrode, confinement is due to gain guiding there.
•Shown to the right are slices of the steady-state optical field near the facets of the straight and tapered sections.•The field near the facet of the tapered section (top) shows the formation of
•As a validation example, a straight waveguide section was simulated using the Utility.
•These results are essentially 2D and may be compared to the those coming directly from LaserMOD.
•The I-V and L-I curves are shown below.
Outline
•Introduction
•Multi-Physics Utility •Solar Cell Utility •Tapered Laser Utility •Multi-Level Simulation
Active Device Simulator rigorous solution of electronic transport, material gain, & optics
System Level Simulator many components, but
simpler models
System level laser
Laser Parameter Extraction
OptSim TM System Level
Simulator
Laser SPICE-like
Electrical Circuit
System Performance
Device Performance LaserMOD TM Active Device Simulator
“Device to
SPICE”
The second type of multi-level interaction involves the passing of spatial data from device to system level. For example, the effects of imperfect coupling between a VCSEL and a multi-mode optical fiber link may be simulated.
ModeSYS TM
LaserMOD TM
System Level Simulator Active Device Simulator
•The near fields or far fields may be simulated in the device tool (LaserMOD).
•These can be passed to multi-mode system tool (ModeSYS).•Then various offsets and angles may be applied to the Spatial Coupler model in ModeSYS to enable the analysis of the impact due to misalignment.
•The system performance in the presence of varying misalignments can be determined without rerunning the device level simulation.
Thank You Q & A。